1987 Volume 28 Issue 4 Pages 257-264
For the purpose of clinical evaluation of aerodynamic conditions in phonation, we developed a system to measure expiratory lung pressure using the airway interruption method, combined with measurements of the air flow rate, vocal pitch and intensity. In this system, an air shutter is connected to the mouthpiece of a PS-77, made by the Nagashima Medical Instrument Co., which measures the air flow rate simultaneously with the vocal pitch and intensity.
The expiratory air flow during sustained phonation is momentrarily interrupted by closing the shutter when the subject holds the mouthpiece airtight with his lips. The air pressure at the shutter is measured at the moment when it reaches equilibrium with the subject's lung pressure.
The output signals of the four parameters are sampled by microcomputer. Time curves of the parameters and sample values at the time point of measurement are displayed on a CRT screen. Data can also be printed out on a recording sheet or stored in a minifloppy disc.
This method is non-invasive and easy for the patient to perform. Our clinical experience has shown this method to be very practical and useful for evaluating aerodynamic conditions in phonation.
